Check valves, particularly ball check valves, are used in a wide variety of fluid flow systems to control and regulate fluid flow. In pump systems, ball check valves are often used to regulate not only on-off flow control, but to regulate other flow characteristics as well. For example, the clearance between the ball valve element and the interior of the valve housing can be used to determine flow rate through the valve, and also to limit the size of solids that can flow through the valve.
In known pump systems, the sizes of the various valves that may be used with a single pump block vary greatly. In such systems, the housing block and/or the inlet and outlet manifolds of the pumps have had to be provided with fittings of different sizes to accommodate the various valves. Thus, if the user of the pump miscalculated the pump requirements, or if the pump requirements changed over time, the user had no recourse but to replace the pump, or replace a substantial number of pump components, in order to change check valves to meet these requirements.
From the foregoing, it can be seen that there exists a need for a modular check valve system in which only the valve unit itself needs to be replaced to change the pump characteristics.